1. Field of the Invention
The present invention relates to soldering electrical components on circuit cards, and, more particularly, to a process for preventing a white residue, commonly associated with soldering using an aqueous-based flux, from forming.
2. Description of Related Art
In the soldering of electrical components on circuit cards using an aqueous-based flux, a "white residue" has been observed when rinsing the soldered circuit card to remove flux residues. While the white residue was believed in the past to be the result of using the aqueous fluxing agent, more recent indications are that the white residue is a result of residual products from the plating process used to form the conductive traces on the circuit card.
The white residue is objectionable, due not only to the appearance, but also because the composition is unknown, and this raises a concern that the residue may somehow be a corrosion product or be corrosive to the soldered joints. Attempts have been made over the years to get rid of the residue, all to no avail. For example, detergents and surfactants have variously been employed, typically in hot water solutions.
Thus, there is a need for a process that can be incorporated in a soldering/cleaning process employing an aqueous-based flux that would prevent the formation of such a white residue.